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*To*: RRRS-AUTHORS@MC.LCS.MIT.EDU*Subject*: changes*From*: Jonathan A Rees <JAR@MC.LCS.MIT.EDU>*Date*: Tue, 1 Apr 86 21:42:41 EST

I intend to add all the hyperbolic trig functions to Scheme. Also, the gamma function, Bessel functions, and Legendre polynomials. I use these all the time and don't know how anyone gets by without them. I think Scheme numbers are really ad hoc. The ring should be a required argument to +, *, etc. so that they know where the answer should come from. (E.g. (+ 4 7 (MOD Z 5)) ==> 1.) Scheme should support arithmetic mod N, polynomial arithmetic, and arithmetic in arbitrary algebraic number fields. Complex number fall out as a special case: (SQRT -1 (MOD (POLY R) (LAMBDA (X) (+ (* X X) 1 R)))) ==> 1i This should be easy to implement. I don't see why we need all these random special forms. For example, there's no need to have QUOTE or LAMBDA. We can write (SET! (X Y Z) (+ X (* Y Z N) N)) instead of (LAMBDA (X Y Z) (+ X (* Y Z N) N)). No ambiguity will result because if the first thing is a list then obviously the expression can't be an assignment. Similarly, we should be writing (SET! (D #(A (B C) 4))) instead of (QUOTE (D #(A (B C) 4))) because what would one-argument SET! mean? I don't understand why there's no existential quantifer in Scheme. For example, I often find myself wanting to write (EXISTS (X) (AND (MEMQ X L1) (MEMQ X L2))) to find out whether the lists L1 and L2 intersect. If we have first-class continuations I don't see any reason why we shouldn't have first-class stores also. E.g. (LET ((Z (CONS 1 2))) (CALL-WITH-CURRENT-STORE (LAMBDA (S) (SET-CAR! Z 3) (LIST (CAR Z) (S (LAMBDA () (CAR Z))))))) ==> (3 1) And while we're on the subject of modules, why don't we just adopt Common Lisp's package system wholesale? It's really useful and elegant. Also Zetalisp's LOOP construct is really good. I'll put all these features in the report (Penguin Books has already expressed interest, by the way) unless people send me enough money. Modestly, Jonathan Rees Editor

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